Celebrity V6-173 2.8L (1989)
Technical Service Bulletin # 901417A
Date: 900201
A/T - Distressed 4TH Clutch Service
Number:
90-141-7A
Section:
7A
Date:
February 1990
Corp. Bulletin No.: 077104
Subject:
DISTRESSED 4TH CLUTCH SERVICE INFORMATION AND PACKAGES
Model and Year:
1989-90 A CARS AND 1990 W CAR WITH 4T60 (440-T4) AND F-7 AUTOMATIC TRANSMISSION
This bulletin covers new channel plate assembly, inside detent lever and manual valve service packages for distressed 4th clutch.
IMPORTANT:
4th Clutch distress may be caused by the manual valve being positioned between the neutral and D4 position. This allows the input
clutch to be applied in 4th gear. The input clutch will try to drive the input sun gear while the 4th clutch is trying to hold the sun
gear. A mispositioned manual shaft may be caused by excessive drag or friction in the range selection system. Contributors to
excessive drag include an improperly routed or binding shift cable and interference between the column and dashboard contact
surfaces. This excessive drag condition may also contribute to a misadjusted shift cable during setting. Also, a mispositioned shift
indicator needle may cause an owner to "line-up" the needle in the D4 or OD position and not allow the manual valve to fully
position in the D4 or OD range. Or an owner that rests his/her hand on the shifter of a console shift model may also be inadvertently
pushing the shifter toward the neutral position.
IMPORTANT:
Possible early signs of 4th clutch distress include a leak from the left axle seal (channel plate side) and/or side cover to channel
plate gasket. The six side cover to channel plate gasket nuts may also have no torque. The heat generated from the 4th clutch
slipping when applied would cause the axle seal and garter spring to expand, causing a leak, and also damage the gasket, leaving
the nuts loose. Other possible early signs may include shudder in 1st gear, slips in all gears and burned transaxle fluid.
A distressed 4th clutch vehicle may not move in drive and reverse. This is due to the 4th clutch assembly being melted or friction welded to the channel
plate. This may lock the 4th clutch hub to the channel plate, causing a tie-up condition when the input clutch is applied. The input clutch is applied in
Park, Reverse, Neutral and Drive ranges at 0 MPH. The vehicle can be pushed with the engine off (when not in park) but when the engine is started, the
vehicle will not move.
For the new service packages, the following parts were modified:
-
New inside detent lever (704) will have the manual link hole location changed for a different "throw" of the manual valve. The previous and new
inside detent lever are not interchangeable even though the parts will physically assemble. The new inside detent lever must be used with the new
manual valve and channel plate. The previous inside detent lever must be used with the previous manual valve and channel plate. The identifier for
the new "W" car inside detent lever is an added square hole. The previous "W" car inside detent lever is gold in color. Some of the early new "W"
car inside detent levers may be gold in color and have the added square hole. The gold color will be discontinued and the square hole will be the
only identfier for the new "W" car inside detent lever. The previous inside detent lever will still be available for models that just need replacement
of the lever for 1987 and prior model years.
-
New manual valve (403) will have changes to the valve lands and be reduced 0.25 mm (0.010") in diameter for the new porting changes to the
service channel plate. The previous and new manual valves are not interchangeable. The new manual valve will assemble into the previous channel
plate but the transaxle will not function because of excessive leakage due to the differences in sizes.
-
New channel plate (404) will have porting changes for the new manual valve and new inside detent lever. The porting changes will help ensure
that two ports will never be opened at once to cause distress to the 4th clutch assembly when the shift cable is not set correctly or is kinked or
binding. The bore for the new manual valve will be reduced to accommodate the manual valve. This will make the new and previous parts
noninterchangeable. The new manual valve and inside detent lever must be used with the new service channel plate. Only the new service channel
plate will be available for 1985-1/2 through 1990 models.
NOTICE:
The new service channel plate assembly must be used with the new manual valve and new detent lever. Using the previous inside detent
lever and the new service channel plate or the new inside detent lever and the previous channel plate will cause durability concerns.
Date of Production Change:
Suspect HYDRA-MATIC 4T60 (THM 440-T4) and THM F-7 transaxies were built from January 2, 1989 (Julian Date 002) through January 15, 1990
(Julian Date 016 with the "E" channel plate shown in Figure 4.
On January 16, 1990 (Julian Date 016) a new channel plate, manual valve and inside detent lever will be used in production that incorporate all the
changes listed in this Service Bulletin. The new channel plate for production will not have an input accumulator bore (the service channel plate will still
have the input accumulator bore). A wave plate and extra input clutch plate will be added to the input housing input clutch that will replace the function
of the input accumulator. These changes will be addressed in another Service Bulletin.
